Recently, over-the-top video (OTT-V) has entered the mainstream of streaming services using the Internet. As a basic technology of OTT-V, Moving Picture Experts Group-Dynamic Adaptive Streaming over HTTP (MPRG-DASH, hereinafter, referred to as DASH) using HTTP through which a supplier and a receiver are connected by point to point in a way similar to a case of browsing a Website (for example, see Non-Patent Literature 1) is known.
According to DASH, adaptive streaming technologies have been achieved. That is, a supplier of content is capable of preparing a plurality of streams of content having identical contents whose image qualities and angle-of-view size are different, and a receiver is capable of switching and viewing an optimal stream according to Internet communication environment and receiver's performance and status.
In DASH, the supplier supplies a metafile called media presentation description (MPD) to the receiver, as information for causing the receiver to adaptively switch streams. In the MPD, an address (URL information) of a source of chunked streaming data (media data such as audio, video, and subtitles) is described. On the basis of the URL information, the receiver accesses a predetermined server, acquires streaming data transmitted via HTTP, and reproduces the streaming data.
FIG. 1 shows a configuration example of a content supplying system for delivering content as a stream on the basis of DASH.
The content supplying system 20 includes a content management server 21, DASH segment streamer 22, and DASH MPD server 23 that are at a content supplier side, and a DASH client 30 at a content viewer side. Note that, though not shown, there are a plurality of the DASH clients 30.
The content management server 21 manages content to be supplied to the receiver, generates pieces of streaming data having different bit rates from content having identical contents, and outputs the generated pieces of streaming data to the DASH segment streamer 22.
The DASH segment streamer 22 divides the streaming data of the content into segments chronologically, converts each segment into a file, retains the files, and notifies addresses of the files to the DASH MPD server 23. In addition, as an HTTP server, the DASH segment streamer 22 transmits the files of the segmented streaming data to the DASH client 30 at the receiver side via the Internet 11 in response to a request from the DASH client 30.
The DASH MPD server 23 generates an MPD describing addresses of sources of the files of the segmented streaming data. In addition, as an HTTP server, the DASH MPD server 23 transmits the MPD to the DASH client 30 at the receiver side via the Internet 11 in response to a request from the DASH client 30.
The DASH client 30 at the receiver side acquires and reproduces the content. Specifically, the DASH client 30 accesses the DASH segment streamer 22 on the basis of the MPD acquired from the DASH MPD server 23, and acquires and reproduces the files of the segmented streaming data.
Note that, it is also possible to provide a cache server on the Internet 11, cache the files of the segmented streaming data and the MPD to be transmitted via HTTP etc., and substitute operations of the DASH segment streamer 22 and the DASH MPD server 23.